Artificial tooth



Patented Feb. l2, ld.

.trak

Lassie ARTIFICIAL TOOTH.

Application led February 21, 1923. Serial No. 629,518.

To @ZZ 'whom it' may conce/ra Be it known that l, BENVENUTO PLATS-GHIGK, a subject of the Kingdom of Italy, and residing at Paris, SeineDepartment, No. Yl2 Rue du Havre, in the Republic of France,manufacturer, have invented certain new and useful Artificial Teeth, ofwhich the following is a specification.

Artificial teeth are usually'provided with cramps or connecting piecesin platinum orother metal adapted to support thel high temperatureswhich are required for the baking of the porcelain used as the materialfor the teeth of a mineral nature. The said cramps are disposed in thepaste before the baking of the teeth and are held in place by reason ofthe transformation of the paste by the high temperature. In some cases,instead of securing the cramps directly in the porcelain, a metal ringis disposed in the paste before baking and is held by the cramps asabove stated. rlhe cramps may be made of any suitable metal or of analloy of nickel, gold-plated or not, and is brazed to the ring by asilver solder.

The present invention relates chiefly to teeth with brazed cramps orconnectingv pieces and has for its subject various improvements in theseteeth.

In the paste of a tooth according to this invention are disposed beforethe backing the rings or like attaching members in platinum or othermetal capable of supporting the high temperatures required for thebacking of said paste. The cramps or connectors in platinum, or alloy ofprecious metals (gold, platinum, palladium) whose melting point is nearthat of platinum, are

brazed with gold which may even be 100%' pure. Inasmuch as the cramp isof platinum ory an alloy having a like melting point, said tooth can beused for all classes of dental work, comprising gold cast under pressureor work which is termed continuous gum work.

Furthermore, in all artificial teeth wherein gold is employed, themineral teeth are secured to the base plate by means of gold brazing ofvarious composition. To secure the mineral teeth to the base plate, itis required to cover the rear surface of the tooth with a plate which isperforated at the requisite points and has the said cramps eX- tendingthrough the same, thus forming a veritable covering for the saidsurface. But the strength of the tooth which is thus faced will chieflydepend upon the greater or less adaptation of the plate to theporcelain. ift has been hitherto a diliicult matter to obtain an exactadaptation, for in spite of the most careful work, it is impossible tosecure the proper fitting of the metal upon the porcelain surface, asthe latter in all classesof manufactured teeth is observed Vto possess arough surface with projections and cavities.

During the brazing process, the brazing metal and the bora-X used forthe melting will enter the'holes provided for the cramps, and crackingis often observed after. cooling. Should this not take place, the platewhich is iinperfectly fitted upon the porcelain will leave a free spacebetween said plate and the porcelain, which will allow particles of foodto enter such spaces, and it becomes impossible to secure thecleanliness which is required in the case of artificial teeth.

Furthermore, if the plate'could be eXactly fitted upon the porcelain,there could be no portion of the cramp left free between the plate andthe rear surface of the porcelain; but if the plate is imperfectly1fitted, a portion of the same will be left free between the inner sideof the plate and the back of the porcelain piece, and this part, underthe effort of the opposite teeth, will be subject to bending anincalculable. number of times during the movement of the jaws, and willbreak much more rapidly than if the plate were exactly fitted upon theporcelain andl if there were so to speak no breach of continuity betweenthe two parts.

According to my invention, an exact fitting is obtained, inasmuch asafter the mounting of the said ring and the baking of the porcelain,each tooth is ground off so as to afford a perfectly plane surface, andit is only after this operation that the cramp or connector is baked tothe ring. The facing plate of gold, which is also plane, can thereforebe fitted exactly upon the surface of the porcelain by reason of thesmall stress which is exerted during the operation of bending andriveting the cramps or connectors.

The following description, together with the `accompanying drawing whichis given by way of example, relates to a tooth which is constructedaccording to this invention, as well as to a tooth of known manufacture.

Fig. 1 shows in vertical section a tooth with` its ring. before thecramp is brazed.

Fig. 2 shows a tooth of the ordinary or non-ground type Which isprovided with a cramp and a facing plate.

Fig. 3 shows a ground tooth according to the invention. which is alsoprovided with a cramp and a facing plate.

F ig. 4 shows a similar tooth with a brazcd projection.

l indicates the ring Which is secured to the tooth 2 during the bakingof the porcelain. The cramp or connecting member is brazed to the ring lby means of the gold portion 3.

According to this invention, the surface 4 of the tooth is carefullyground oil before placing the cramp in position, so as to be perfectlyplane and to it exactly upon the plate 5 Which is brazed at 6 to thecramp.

It will be observed in Fig. 2 that when the tooth is not ground off. thefacing plate will not fit exactly upon the same. During the brazingoperation, the borax would infiltrate into the spaces 7 between the saidplate and the tooth, and would subsequently7 occasion the rupture of thetooth. The said a;

been inserted and after baking, but before the anchors are attached.

In testimony7 that I claiinthe foregoing as my invention I have signedmy name in presence of a subscribing Witness.

BENVENUTO PLATSCHICK.

Witness:

MAURICE ROUX.

